Hepatic Mastocytosis in Japanese Black Cattle

Abstract

In 5 Japanese Black steers (2-2.4 years old) that originated from 5 different feedlots, the livers were found at slaughter to have multiple nodular or cordlike lesions (5 steers) and an extensive fibrotic area (1 steer). Microscopic changes included extensive fibroplasia in the portal tracts and chronic proliferative endophlebitis-like lesions confined to the portal vein branches. Fibroplasia was much more prominent in the macroscopic fibrotic lesion of 1 steer. Portal vein branches presented irregular variciform dilation of the vascular lumen and fibroplastic changes in the subendothelial areas that showed occasional hemorrhage and were simultaneously infiltrated with large numbers of mast cells and moderate to large numbers of eosinophils. Within these subendothelial regions, not only did mast cells exhibit cytologically atypical features, but they also formed multifocal nodules. The venous lesions may represent a variant of mastocytosis with specific involvement of the hepatic portal vein branches in cattle.

Pathology and Pathogenesis of Immune-Mediated Diseases of Animals

“…8 Hepatic mastocytosis in Japanese Black cattle is described for the first time in this issue by Ohfuji. 15 A relationship between immune cell neoplasia and chronic inflammation is suggested by Matsumoto, Uchida, Nakashima, et al in an article describing high levels of IgA specific for gliadin and tissue transglutaminase in dogs with intestinal T cell lymphoma. 24 The serologic data combined with known diagnostic challenges of differentiating chronic enteritis from lymphoma lead the authors to hypothesize that intestinal lymphoma arises following chronic antigenic stimulation by dietary proteins in susceptible animals.…”